Heart valve prosthesis

ABSTRACT

A heart valve prosthesis has a frame that includes at least one outwardly extending annular flange adjacent to a suturing ring and a band comprising an inwardly extending annular flange that is capable of engagement with the annular flange of the frame. A tortuous path is formed between the annular flange of the frame and the annular flange of the band that can engage and restrain a suture placed between them. One or more split portions or tab portions on the band are adapted to lock the band in engagement with the flange of the frame. Such a device can be used to more easily replace a heart valve by advancing a sutures through a suturing ring on the valve and the valvular rim such that they are brought outward of the flange extending from the frame and then advancing the band over the valve and over the sutures at a proximal, outflow end of the valve until the band engages the flange and captures the sutures between the band and the flange.

[0001] This application is a continuation-in-part of Ser. No. 10/196,527filed Jul. 16, 2002, which is incorporated by reference herein in itsentirety.

FIELD OF THE INVENTION

[0002] This invention relates generally to implantable heart valveprostheses, particularly to improvements in a heart valve prosthesisfacilitating initial implantation of the suturing ring and replacementof a chronically implanted heart valve mechanism supported by thesuturing ring providing enhanced durability reliability, ease of use,and ease of manufacture.

BACKGROUND OF THE INVENTION

[0003] Implantable heart valve prostheses have been used to replacevarious diseased or damaged natural aortic valves, mitral valves,pulmonic valves and tricuspid valves of the heart. The aortic and mitralvalves are most frequently replaced due to heart disease, congenitaldefects or injury. The mitral valve controls the flow of blood betweenthe left atrium and the left ventricle and the aortic valve controls theblood flow from the left ventricle into the aorta. Generally, the knownheart valve prostheses are either bioprostheses or mechanical heartvalve prostheses.

[0004] The bioprostheses or “tissue valves” are generally made of asuitable animal tissue, e.g., harvested swine valve leaflets, mountedonto a stationary metal or plastic frame, referred to as a “stent”.Exemplary tissue valves formed of swine valve leaflets mounted to strutsof a stent are those disclosed in U.S. Pat. Nos. 4,680,031, 4,892,541,and 5,032,128 as well as the MEDTRONIC® Hancock II and Mosaic® stentedtissue valves. Some prosthetic tissue valves are formed from treatedintegral swine valve leaflets and valve annulus structure, e.g. theMEDTRONIC® Freestyle®) stentless aortic root bioprostheses Modernmechanical heart valve prostheses are typically formed of an annularvalve seat in a relatively rigid valve body and one or more occludingdisk or pair of leaflets that is movable between a closed, seatedposition in the annular valve seat and an open position in a prescribedrange of motion. Such mechanical heart valves are formed of bloodcompatible, non-thrombogenic materials, typically currently comprisingpyrolytic carbon and titanium. Hinge mechanisms and/or pivoting guidesentrap and prescribe the range of motion of the disk or leaflets betweenopen and closed positions. Exemplary bi-leaflet mechanical heart valvesare disclosed in commonly assigned U.S. Pat. Nos. 4,935,030 and6,139,575 and in U.S. Pat. Nos. 6,176,877 and 6,217,611.

[0005] Mechanical and tissue valves have advantages and disadvantages.By their very nature, mechanical heart valves have metal or plasticsurfaces exposed to the blood flow, which remain thrombogenic even longtime after their implantation by major surgery. The opening and closingof mechanical heart valve occluders can damage blood elements andtrigger a coagulent cascade. Blood flow disturbances in certainmechanical valves are also believed to aggravate blood coagulation.Therefore, patients having such mechanical heart valves can avoidpotentially life threatening embolus formation only by takinganti-thrombogenic or anti-coagulent medication on a regular basis.Porcine tissue valves include three cusps or leaflets of a heart valveexcised from pigs and preserved by treatment with glutaraldehyde. Thepreserved porcine tissue is thrombogenic, and therefore, the humanpatient takes anti-thrombogenic or anti-coagulent medication at least aperiod of time after the surgical implantation of a tissue valve. Valveleaflet opening and closing characteristics and blood flow past opentissue leaflets of tissue valves can be superior to those afforded bymechanical valves. However, tissue leaflets can become calcified overtime distorting the leaflet shape and ultimately leading to failure ofthe tissue leaflets to fully close or open. Proposals have been advancedto form mechanical heart valve prostheses from flexible,anti-thrombogenic, polymeric sheets or fabrics that are resistant tocalcification mounted to stents to function like stented tissue valvesalso been proposed as exemplified by U.S. Pat. Nos. 5,562,729. However,calcification and tear issues of polymeric materials remain to be solvedbefore a polymeric valve can be realized.)

[0006] Such mechanical and tissue valve prostheses are intended to besutured to peripheral tissue of a natural heart valve orifice (the“valvar rim”) after surgical removal of damaged or diseased naturalvalve structure. Modern prosthetic heart valves are typically suppliedwith a sewing or suturing ring surrounding the valve body or stent thatis to be sutured by the surgeon to the valvar rim. Suturing ringstypically comprise a fabric strip made of synthetic fiber that isbiologically inert and does not deteriorate over time in the body, suchas polytetrafluoroethylene (e.g., “Teflon PTFE”) or polyester (e.g.,“Dacron”), that is woven having interstices permeable to tissueingrowth. The valve body or stent is typically circular or ring shapedhaving an outer surface or sidewall shaped to fit with an inner sidewallof the suturing ring. In some cases, the suturing ring fabric is shapedto extend outward to provide a flattened collar or skirt that can beapplied against and sutured to the valvar rim, as shown for example inU.S. Pat. No. 3,997,923.

[0007] It is proposed in the prior art to make the valve body or stentrotatable within the annulus of the suturing ring. The surgeon can firstsuture the suturing ring to the valvar rim and then rotate the valvebody or stent within the annulus of the suturing ring in order to adjustthe angular orientation of the valve mechanism in the path of bloodflow. In this way, the valve mechanism can be rotated to minimizeinterference with the adjacent heart structure or to divert blood flowpast the open valve leaflet(s) in an optimal flow direction. Suchrotation of the valve mechanism with respect to and within the annulusof the suturing ring requires a rotational torque sufficiently small asto avoid damage to the sutured valvar rim or loosening of the sutures,and yet sufficiently great so that the valve mechanism, when properlypositioned, does not further rotate during chronic implantation.Moreover, the configuration and attachment methods should be such as toprovide highly reproducible rotational torques so as to maximizeproductivity in manufacture and minimize scrap and rework.Configurations and methods of attaching suturing rings to annular valvebodies to satisfy these requirements are disclosed in the prior art,e.g., those described in the above-referenced '240 patent and in U.S.Pat. Nos. 5, 071,431, 5,397,346, 5,876,436, 6,113,632 for example.However, none of the current available tissue valves allows a surgeon torotate the stent within the suturing ring because the suturing ring isan integral part of the stent.

[0008] Most suturing rings are formed of a radiopaque stiffening ring orband formed of stainless steel or titanium having an inner annular walland an outer wall extending between axial ends of the band. The fabricis affixed either to the outer wall of the stiffening band as disclosed,for example, in the above-referenced '632 patent or surrounds thestiffening band as disclosed, for example, in the above-referenced '240patent. The stiffening band of the '240 is a split band formed withsplit ends that are drawn against one another during assembly of thesuturing ring about the valve stent or body to reduce the inner diameterof the split band in order to overcome difficulties encountered infabrication employing a continuous ring or band that are described indetail in the '240 patent. The split ends are held together by a cord orheat shrink band or shape memory alloy band that is encased within thefabric when the fabric is sutured together. The interior space withinthe fabric can be filled with an elastomeric compound.

[0009] Separation of the finished suturing ring from the valve body orvalve stent to replace the mechanical or tissue valve is not suggestedin the '240 patent. Any attempt to do so by cutting the suturing ringassembly apart where the split ends abut one another would effectivelydestroy the suturing ring. Moreover, it would not be possible to locatethe split ends beneath the fabric without disassembling the fabric aswell as the cord or band.

[0010] Despite improvements in longevity, adverse reactions andcomplications with implanted mechanical heart valves and tissue valvesof the types described above requiring surgical replacement can occurfrom time-to-time during the lifetime of a patient. It has long beenrecognized that it is desirable to avoid removing and replacing thesuturing ring if it is intact and is not implicated in the adversereaction or complication. Removal of the existing sutures to remove thesuturing ring and restitching of a new suture ring in place cancompromise the integrity of the valvar rim and lead to further recoverycomplications, morbidity and mortality. Therefore, attachment anddetachment structures and methods have been proposed to enable theremoval of the defective mechanical or tissue valve from the suturingring and insertion of a replacement mechanical or tissue valve into theannulus of the suturing ring sutured to the valvar rim.

[0011] In one approach disclosed in the above-referenced '128 patent,the valve stent is sutured to the suturing ring upon initialimplantation. Replacement of the tissue valve involves severing thesutures by a scalpel worked between the suturing ring annulus,withdrawing the released tissue valve, inserting a new tissue valve intothe ring annulus and suturing it in place. This approach requires avalve design that can be stitched in place in the suturing ring annulus,does not allow the tissue valve to be easily rotated in the suturingring in the manner described above, and requires considerable care andtime to execute. Pannus overgrowth and calcification of the surfaces atthe junction between the valve stent and the suturing ring occur overtime that must be cut away or through without damaging the suturingring. Consequently, other approaches have been devised allowing rotationof the replacement tissue or mechanical valve within the suturing ringannulus.

[0012] A detachable suturing ring having a shape-memory member thatexpands in diameter when cooled below blood temperature to allow releaseand replacement of a valve body or stent is disclosed by J. Jansen etal. in “Detachable Shape-Memory Sewing Ring for Heart Valves”,(Artificial Organs, vol. 16, No. 3, pp. 294-7, 1992). While thisapproach would appear to be very beneficial, it has not been establishedthat the temperature induced shape changes are robust enough to assureretention of the tissue or mechanical valve or large enough when cooledby cooling fluid to expand a chronically implanted suturing ring toallow removal of a valve body or stent. Pannus overgrowth andcalcification about the suturing ring would likely reduce the amount ofexpansion or prevent any appreciable expansion of the ring when it iscooled in the attempt to expand it. Moreover, this concept isimpractical because of high cost and difficulty in fabrication.

[0013] More typically, it has been proposed to use an interlockingmechanism of the suturing ring and the valve body or stent that can beoperated by the surgeon to detach or attach valve body or stent from orto the suturing ring. Mating male and female screw threads, snaps,fabric hooks, screws, or other interlocking mechanisms are disclosed inthe above-referenced '031 patent, '923 patent, '541 patent, and in U.S.Pat. Nos. 3,997,923, 4,078,268, 4,506,394, 4,705,516, 4,790,843,6,217,611 and Re.31,040, for example.

[0014] These interlocking mechanisms necessarily must be robust enoughto ensure that they do not fail during chronic implantation therebyloosening or releasing the tissue or mechanical valve and endangeringthe life of the patient. The interlocking mechanisms must be largeenough to be readily manipulated and to not become frozen due tocoagulation or exposure to blood and fluids. On the other hand, theinterlocking mechanism must be minute in size in order to avoid takingup space that would reduce the size of the valve annulus or interferewith leaflet function. Consequently, none of these proposed interlockingmechanisms have been adopted.

[0015] In the following description and claims, the term “heart valvemechanism” embraces a tissue valve mechanism comprising a stentsupporting tissue leaflet(s) and a mechanical heart valve mechanismcomprising a heart valve body supporting a pivotal disk or leaflet(s).For convenience, the term “valve frame” means a stent of a tissue valveor a valve body of a mechanical heart valve or equivalents thereof, andthe term “occlude” means tissue leaflets of a tissue valve or pivotaldisk or leaflets of a mechanical heart valve or equivalents thereof. Theassembly of a tissue or a mechanical heart valve mechanism with asuturing ring can be characterized as a heart valve prosthesis.

[0016] Thus, there remains a need for improvements in suturing ringsthat facilitate the initial implantation and replacement of chronicallyimplanted heart valve mechanisms supported by the suturing rings. Amongother things, there remains a need for suturing rings that are separablefrom the heart valve mechanisms that can accommodate a variety of heartvalve mechanisms including either tissue valves or mechanical heartvalves of differing designs and that are highly versatile in useincluding potential use in minimal invasive surgery techniques. Thereremains a need for such suturing rings that have a locking mechanismthat does not add bulk to the suturing ring or diminish the suturingring and valve annulus, that are simple to manufacture and use, and thatare robust, durable and reliable. There remains a need for a separatesuturing ring that facilitate surface modification of the suturing ringfabric without affecting tissue valve leaflets and that is free ofglutaraldehyde employed to preserve the tissue leaflets prior toimplantation.

SUMMARY OF THE INVENTION

[0017] The present invention is directed toward providing an improvedinterlocking mechanism and methods of interlocking a suturing ring witha valve frame of a valve mechanism that facilitates the initialimplantation and replacement of a chronically implanted heart valvemechanism supported by the suturing ring, that is robust, that does notdiminish the valve annulus, and that provides enhanced durability,reliability, ease of use during initial implantation and duringreplacement surgery, and simplified manufacture. Other advantages of thepresent invention will be made apparent in the following.

[0018] In accordance with a first aspect of the invention, the suturingring annulus is adjustable to receive and engage the valve frame of theheart valve mechanism within the annulus. An interlocking mechanismapplies restraint to fix the adjusted suturing ring annulus engagedagainst the valve frame to support the heart valve mechanism duringchronic implantation.

[0019] The surgical steps of initially implanting a tissue valve ormechanical valve of the present invention are greatly simplified by thepresent invention. Moreover, the surgeon can employ the optimal one ofseveral alternative ways of initially implanting the suturing ring to avalvar rim. The valve frame is inserted into the suturing ring annuluswhile adjusting the suturing ring annulus to seat the valve frame withinthe suturing ring annulus and operating the interlocking mechanism toapply restraint to the adjusted suturing ring annulus in seatedengagement against the valve frame to retain the valve frame in thesuturing ring annulus during chronic implantation of the heart valveprosthesis. The suturing ring can be sutured to the valvar rim eitherbefore or after inserting the valve frame in the suturing ring annulusor operating the interlocking mechanism.

[0020] The surgical steps of replacing a tissue valve or mechanicalvalve at a later time are also greatly simplified by the presentinvention. A dysfunctional valve mechanism is removed from the suturingring annulus by operating the interlocking mechanism to release theapplied restraint, unseating the heart valve frame from the suturingring annulus, and removing the dysfunctional heart valve prosthesis fromthe suturing ring annulus. The valve frame or integral suturing ring ofa replacement new heart valve mechanism is inserted into the suturingring annulus while adjusting the suturing ring annulus to seat the valveframe within the suturing ring annulus. The interlocking mechanism isthen operated to apply restraint to the adjusted suturing ring annulusin seated engagement against the valve frame to retain the valve framein the suturing ring annulus during chronic implantation of thereplacement heart valve prosthesis. Advantageously, this process allowsthe dysfunctional valve mechanism to be replaced by the same or adifferent type of heart valve mechanism.

[0021] In another approach, the chronically sewn-in suturing ring canalso be used as a “docking station” for an incompatibly dimensionedheart valve prosthesis that comprises a valve mechanism supplied with anintegral suturing ring about the valve frame. In this case, the integralsuturing ring of the new valve prosthesis can be placed within or overthe annulus of the chronically sewn-in suturing ring and sutures can besewn through them to join them together.

[0022] In a preferred embodiment, a suturing ring is formed of agenerally annular, split stiffening band extending between opposed bandsplit ends to which a suturing ring fabric is attached. The band splitends are separated apart by a gap such that a first annulus diameter ofthe annulus of the suturing ring is defined when the suturing ring isunrestrained. The suturing ring is adapted to be surgically attached, asby suturing, to a prepared valvar rim of a patient's heart with thesuturing ring unrestrained. The suturing ring first annulus diameter issized to enable a valve body of a mechanical heart valve or a stent of atissue valve or other valve frame to be inserted into the suturing ringannulus and rotated therein to a desired orientation. The suturing ringannulus diameter can be increased manually or by an instrument toreceive the valve frame.

[0023] The band split ends can then be restrained such that a secondinterior diameter of the suturing ring is defined when the suturing ringis restrained that interference fits with and engages the valve frameexterior surface. An interlocking restraint is preferably accomplishedby one or more of sutures, clamps, hooks, teeth, buttons, or otherlocking mechanisms that can be released even after chronic implantationso that the heart valve mechanism can be replaced.

[0024] A preferred restraint comprises the use of one or more sutureattached to suture retention mechanisms at the first and second bandsplit ends. The suture can be sewn through a suture hole extendingthrough each one of the opposed band split ends and the suture ringfabric overlying the suture holes. The suture ends are drawn tight todraw the band split ends toward one another, and the suture ends areeither tied off or thermally welded together. Preferably, the fabric ismarked or colored to indicate where the suture is located.

[0025] Preferably, the interior surface of the split stiffening band isshaped in a complimentary mating fashion to the exterior surface of thevalve frame to entrap or lock the surfaces together when the band splitends are drawn together and restrained.

[0026] Moreover, the valve replacement process of the present inventionadvantageously preserves the healed annulus and the healed suturingring, is faster and relatively easier than surgically cutting away thesuturing ring and replacing it, and should reduce morbidity andmortality associated with current replacement procedures

[0027] In a further aspect of the invention, the sewing of the suturingring to the valvar rim in the initial implantation is simplified, andsuture knots about the suturing ring surface can be eliminated orminimized in size and number. In this aspect, the plurality of suturesthat are sewn through the valvar rim around its circumference areextended through the suturing ring annulus and suture segments areentrapped within the space between the suturing ring annulus and theouter wall of the valve frame. Then, the free ends of the sutures aretrimmed. The relatively bulky knots that can be foci of coagulation orthrombus formation, can abrade tissue valve leaflets, and can interferewith blood flow or valve operation, are eliminated.

[0028] In one simple implementation of this further aspect, the suturesare sewn through suture routing guides for routing a plurality ofsutures generally equally spaced apart through the suturing ringannulus. The suture guides can comprise an axial end band or both axialend bands of the suturing ring fabric sewn to the suturing ring that thesutures are sewn through at spaced apart locations around thecircumference of the suturing ring so as to support the suturing ringand to maintain the sutures generally evenly spaced apart alongside thestiffening band interior side wall.

[0029] In a further implementation of this second aspect, a plurality ofspaced apart suture guides are preferably formed in the stiffening bandto dispose a plurality of sutures spaced apart from one another andextending within the suturing ring annulus alongside the interior bandsidewall. The suture guides can be a plurality of suture holes arrayedaround the circumference of the generally annular split stiffening bandthat facilitate suturing of the suturing ring to the prepared valvarrim. The suture holes preferably extend through at least a portion orportions of the split stiffening band that is or are shaped in acomplimentary mating manner to the exterior surface of the valve framewhereby at least a portion of each suture is entrapped therebetween whenthe band split ends are drawn together and restrained. Alternatively,the sutures can be extended through an array of preformed holes or slotsthrough the split stiffening band that are also used in stitching thesuturing ring fabric to the split stiffening band.

[0030] The sutures can be routed through the suture guides and a portionof the suturing ring, and the suture ends can be tied by simple singleor double hitches that are smaller and easier to tie than square knotstying two suture ends together.

[0031] In a preferred embodiment of the further aspect, the interiorsurface of the split stiffening band is formed with a pair of bandflanges extending outwardly from the stiffening band inner surface andspaced apart to define a groove therebetween that is dimensioned toreceive an outwardly extending stent flange of the valve frame when theband split ends are drawn together and restrained. A plurality ofaxially aligned pairs of suture holes are formed through the bandflanges arrayed about the circumference of the split stiffening band,whereby one or more suture can be extended through each axially alignedpair of suture holes and across the intervening groove. The sutures canbe employed to suture the suturing ring to the valvar rim, and are thenentrapped within the groove by the stent flange when the band split endsare drawn together and restrained.

[0032] Furthermore, the band flanges are preferably notched to theflange edges at the suture holes to enable the one or more suture to belaterally, rather than axially, inserted into the axially aligned sutureholes.

[0033] Tissue ingrowth into the interstices of the suturing ring fabricoccurs in time, and the sutures may become unnecessary to retain thesuturing ring in place. However, it is preferable to create a singlehitch or double hitches of the suture ends to the suturing ring fabric.It is therefore possible to employ the chronically implanted suturingring in the replacement procedures described above.

[0034] Alternatively, a single running suture or sets of sutures can besewn through the suturing ring annulus and adjoining valve rim tissue atmultiple points around the circumference of the suturing ring. In thisway, multiple segments of the single suture are entrapped between thesuturing ring annulus and the valve frame and the number and size ofsuture hitches are minimized.

[0035] A number of advantages can be realized from the above-describedfirst and second aspects of the invention practiced collectively orseparately in either or both of an initial implantation of the separatesuturing ring and heart valve mechanism or a replacement of adysfunctional heart valve mechanism in a chronically implanted suturingring of the present invention.

[0036] The above-described procedures for implanting the suturing ringadvantageously allows the physician to view the placement of suturesthrough the open suturing ring annulus rather than having that viewblocked by the heart valve mechanism. The suturing of the suturing ringto the valvar rim is greatly simplified, and errors are reduced.Moreover, the procedure may lend itself to minimum invasive surgerytechniques.

[0037] In addition, the suturing ring collar that sutures are normallysutured through can be eliminated (or minimized to the extent needed toeffect proper sealing against the valvar rim). Therefore, the suturingring can have any shape. Since suturing is through the suturing ringannulus, the surgeon can select a larger diameter suturing ring capableof supporting a larger heart valve mechanism in the suturing ringannulus to optimize valve function.

[0038] In yet another aspect of the invention, a heart valve prosthesishas a frame that includes at least one outwardly extending annularflange adjacent to a suturing ring and a band comprising an inwardlyextending annular flange that is capable of engagement with the annularflange of the frame. A tortuous path is formed between the annularflange of the frame and the annular flange of the band that can engageand restrain a suture placed between them. One or more split portions ortab portions on the band are adapted to lock the band in engagement withthe flange of the frame. Such a device can be used to more easilyreplace a heart valve by advancing a sutures through a suturing ring onthe valve and the valvular rim such that they are brought outward of theflange extending from the frame and advancing the band over the valveand over the sutures at a proximal, outflow end of the valve until theband engages the flange and captures the sutures between the band andthe flange. The split portions or tab portions in the band can be usedto lock the band to the flange.

[0039] Finally, a surgeon can attach the suturing ring to the valveframe and then implant the heart valve prosthesis in the conventionalmanner. Thus, the suturing ring can be used in a variety of ways meetingthe preferences of the surgeon in any particular case.

[0040] Tissue valves are supplied immersed in toxic glutaraldehyde insterile containers until they are used. The suturing ring fabric and anyelastomeric filler of such conventional tissue valves are also immersedin the glutaraldehyde. During implantation of such tissue valves, it isnecessary to rinse the tissue valves for some time to reduce theresidual glutaraldehyde. Usually, the valvar rim site is prepared andsized before an appropriately sized tissue valve is selected. Then, therinsing must take place. The present invention offers the furtheradvantages of supplying the suturing ring in a sterile container devoidof glutaraldehyde, so that it does not require rinsing, and directcontact of residual glutaraldehyde with the valvar rim tissue iseliminated. Overall procedure time can be saved in the procedure byattaching the suturing ring to the valvar rim while the tissue valvemechanism is being rinsed.

[0041] The fabric covering of suturing rings can also be surface treatedduring manufacture to reduce calcification or thrombus formation withoutaffecting the heart valve body and occluder(s) or stent and tissueleaflets since they are manufactured separately.

[0042] This summary of the invention and the advantages and featuresthereof have been presented here simply to point out some of the waysthat the invention overcomes difficulties presented in the prior art andto distinguish the invention from the prior art and is not intended tooperate in any manner as a limitation on the interpretation of claimsthat are presented initially in the patent application and that areultimately granted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] These and other features and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription of a preferred embodiment, especially when considered inconjunction with the accompanying drawings in which:

[0044]FIG. 1 is a perspective view of the assembly of a suturing ringand stent of a tissue valve formed in accordance with the presentinvention;

[0045]FIG. 2 is a perspective view of the stent of FIG. 1 arranged to beinserted into the annulus of the suturing ring of FIG. 1;

[0046]FIG. 3 is a side elevation view of the stent frame of the stent ofFIG. 2;

[0047]FIG. 4 is a side elevation view of the split stiffening bandenclosed within the suturing ring of FIGS. 1 and 2;

[0048]FIG. 5 is a perspective view of the split stiffening band enclosedwithin the suturing ring of FIGS. 1 and 2;

[0049]FIG. 6 is a perspective view of the released assembly of a furtherembodiment of the suturing ring of FIGS. 1 and 2 and a valve body of amechanical valve formed in accordance with the present invention;

[0050]FIG. 7 is a perspective view of the tightened assembly of thesuturing ring of FIG. 6 about the outer wall of the valve body of themechanical valve of FIG. 6;

[0051]FIG. 8 is a cross-section view taken along lines 8-8 of FIG. 1illustrating the mating engagement of the fabric covered splitstiffening band of the suturing ring against the outer wall of thefabric covered stent;

[0052]FIG. 9 is a cross-section view taken along lines 9-9 of FIG. 7illustrating the mating engagement of the fabric covered splitstiffening band of the suturing ring against the outer wall of the valvebody;

[0053]FIG. 10 is an illustration of one method of securing the suturingring to the valvar rim employing sutures through the suturing ringfabric;

[0054]FIG. 11 is an illustration of a further method of securing thesuturing ring to the valvar rim employing sutures extending inside thesuturing ring annulus in accordance with the second aspect of theinvention;

[0055]FIG. 12 is an illustration of the valve stent seated into thesuturing ring annulus enabling the assembly to be advanced along thetaut sutures and seated firmly against the valvar rim when the fabriccovered, split stiffening band is restrained and the sutures areentrapped between the suturing ring inner wall and the stent outer wall;

[0056]FIG. 13 is a cross-section view taken along lines 13-13 of FIG. 12illustrating the entrapment of a suture between the inner wall of thesuturing ring and the outer wall of the stent;

[0057]FIG. 14 is a further cross-section view taken along lines 9-9 ofFIG. 7 illustrating the entrapment of a suture between the inner wall ofthe suturing ring and the outer wall of the valve body of a mechanicalheart valve;

[0058]FIG. 15 is a further cross-section view taken along lines 13-13 ofFIG. 12 illustrating alternative configurations of the inner wall of thesplit stiffening band and the outer wall of the stent facilitating theentrapment of a suture between the inner wall of the suturing ring andthe outer wall of the stent;

[0059]FIG. 16 is a still further cross-section view taken along lines13-13 of FIG. 12 illustrating alternative configurations of the innerwall of the split stiffening band and the outer wall of the stentfacilitating the entrapment of a suture between the inner wall of thesuturing ring and the outer wall of the stent;

[0060] FIGS. 17-19 are plan schematic views of the split stiffening bandillustrating an alternative or additional restraint mechanism forclosing and opening the split stiffening band;

[0061]FIG. 20 is a flow chart illustrating one preferred embodiment ofinitially implanting a suturing ring and heart valve mechanism to form aheart valve prosthesis in accordance with the present invention;

[0062]FIG. 21 is a perspective view of a stent arranged to be insertedinto the annulus of a suturing ring of the present invention sutured bya single running suture to a valvar rim;

[0063]FIG. 22 is a perspective schematic view of a suture ring holderengaging the suturing ring by severable sutures to enable positioningand suturing of the suturing ring to the valvar rim; and

[0064]FIG. 23 is a perspective schematic view of a stent holder engagingthe stent frictionally or by severable sutures to enable positioning ofthe stent into the suturing ring.

[0065]FIGS. 24a-b are plan schematic views of one embodiment in which aband engages a circumferential frame portion on a valve body in order tocapture sutures securing the valve to a valvar rim.

[0066]FIGS. 25a-b are plan schematic views of another embodiment inwhich a band engages a circumferential frame portion on a valve body inorder to capture sutures securing the valve to a valvar rim.

[0067]FIG. 26a is a perspective view of the band shown in FIG. 25a.

[0068]FIG. 26b is a cross sectional view of the band of FIG. 26a takenalong the line 26 b-26 b.

[0069]FIG. 26c is a cross sectional view of the band of FIG. 26a takenalong the line 26 c-26 c.

[0070]FIG. 26d is a partial perspective view of yet another embodimentof a band similar to that shown in FIG. 26a.

[0071]FIG. 26e is a partial perspective view of yet another embodimentof a band similar to that shown in FIG. 26a

[0072]FIG. 27a is a cross sectional view of the band and frame portionof FIG. 25a moving into engagement.

[0073]FIG. 27b is a cross sectional view of the band and frame portionof FIG. 27a in an engaged and locked position.

[0074]FIG. 28a is a cross sectional view of the engaged band taken atthe cross section of FIG. 26b with the frame portion of FIG. 25a.

[0075]FIG. 28b is a cross sectional view of the engaged band taken atthe cross section of FIG. 26c with the frame portion of FIG. 25a.

[0076]FIG. 29a is a perspective view of the band of FIG. 25a engagedwith a band applicator tool for applying it to a frame portion as inFIGS. 25a-b.

[0077]FIG. 29b is a cross sectional view of the band applicator tool andband of FIG. 29a.

[0078]FIG. 29c is an exploded perspective view of an alternative bandapplicator tool.

[0079]FIG. 29d is a perspective view of the applicator tool of FIG. 29cengaged with a band

[0080]FIG. 30a is a plan schematic view of the valve of FIG. 25aincluding a valve holder tool and a suture tensioning tool.

[0081]FIG. 30b is a perspective view of the suture tensioning tool ofFIG. 30a.

[0082]FIG. 31 is a perspective view of the valve and valve holder toolof FIG. 30a with the band and band applicator tool of FIG. 29a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0083] The present invention can be implemented to improve implantationprocedures and performance of a wide variety of heart valve prosthesesof the various types currently existing or that may come into existencethat are surgically attached to a prepared valvar rim. As noted above,the present invention involves improved suturing rings that supportremovable heart valve mechanisms, e.g., tissue valves and mechanicalheart valves comprising a heart valve frame and occluder. The valveframes described in the exemplary embodiments are a tissue valve stentor a mechanical valve body, and the occluders include tissue leaflets ofa tissue valve or pivotal disk or leaflets of a mechanical heart valve.The various aspects of the present invention may be utilized inattaching any such valve frame or any other valve frames that aredevised in the future to a suturing ring.

[0084] Thus, for example, FIGS. 1-3 depict a suturing ring 10 that isemployed to support a fabric covered stent 40 of a tissue valvemechanism, and FIGS. 6 and 7 depict a suturing ring 10′ that is employedto support a valve body 50 of a mechanical heart valve mechanism. Thetissue leaflets supported by stent 40 are not show in the figures forconvenience of illustrating the aspects and embodiments of the presentinvention. The stent 40 and tissue leaflets can take any of the formsknown in the art such as those described in the background of theinvention. Similarly, the pivotal disk or leaflet(s) and the valve seatand the hinging mechanisms of the valve body 50 enabling and controllingmovement of the pivotal disk or leaflets may take any of the forms knownin the art and are not shown in any of the figures for convenience ofillustrating the aspects and embodiments of the invention.

[0085] In the first aspect of the present invention, the suturing rings10 and 10′ are formed of a generally annular, split stiffening band 12depicted in FIGS. 2, 4 and 5 extending longitudinally between opposedband split ends 14 and 16 and that supports a stent fabric 32. The splitstiffening band 12 can be formed of a biocompatible metal, e.g.,titanium or tantalum, a plastic material, e.g., Delrin® plastic,reinforced pyrolytic carbon or of other material. The split stiffeningband 12 has an interior band sidewall 18 formed with an outwardlyextending annular groove 22 that engages the stent 40 as describedfurther below and an exterior band sidewall 20 that is generally flatbut may have any shape. The inner and exterior band sidewalls 18 and 20are joined at the opposed band split ends 14 and 16 and at the upper andlower axial ends 24 and 26. A plurality of upper and lower suturereceiving slots 28 and 30 extend through the inner and exterior bandsidewalls 18 and 20 so that the suturing ring fabric 32 can be suturedto the split stiffening band 12.

[0086] The suturing ring fabric 32 comprises a fabric strip made ofsynthetic fiber, such as polytetrafluoroethylene (e.g., “Teflon TFE”) orpolyester (e.g., “Dacron”), of a mesh weave having interstices permeableto tissue ingrowth. The longitudinal edges of the fabric strip are sewntogether to form longitudinal seams. One longitudinal seam is wrappedover the upper axial end 24, fitted against the interior band sidewall18 over the set of upper slots 28, and the fabric strip is sewn togetherthrough the set of upper slots 28. The other longitudinal seam iswrapped over the lower axial end 26, fitted against the interior bandsidewall 18 over the set of lower slots 30, and the fabric strip is sewntogether through the set of lower slots 30. The ends of the fabric stripare sewn together over the gap G (FIG. 4) separating the opposed bandsplit ends 14 and 16 in the suturing ring 10 or left separated at theopposed band split ends 14 and 16 in the suturing ring 10′. In this way,groove 22 remains exposed, and the fabric strip is thereby formed into atorus shaped or annular shaped suturing ring fabric 32. The shape of thesuturing ring fabric 32 may be relatively flat if the suturing ring isintended to be used in aortic valve replacement as shown in theabove-referenced '575 patent. Suturing rings for heart valves intendedfor mitral valve replacement have pronounced radially extending flangesor skirts or collars formed of a wider fabric strip that is sewn orfilled as shown, for example, in the above-referenced '030 and '346patents, respectively. The suturing ring fabric 32 may also be filledwith a biologically acceptable, spongy material, such as silicone rubberor polyurethane or hydrogel, and the filled suturing ring fabric 32 maybe formed and shaped as desired. However, the resulting suturing ringfabric 32 may have any desired cross-section profile.

[0087] As shown in FIG. 4, the band split ends 14 and 16 are separatedapart by a gap G such that a first annulus diameter AD1 of the annulusof the suturing ring 10 is defined when the suturing ring 10 isunrestrained. The split stiffening band 12 is resilient, and the splitstiffening ends 14 and 16 can be separated apart to widen gap G andincrease the first annulus diameter AD1 to a second annulus diameter AD2that accommodates a somewhat larger diameter valve frame or broughttogether to decrease gap G and the first annulus diameter AD1 to thesecond annulus diameter AD2 to accommodate a somewhat smaller diametervalve frame.

[0088] The suturing ring 10 is adapted to be surgically attached, as bysuturing, to a prepared aortic or mitral valvar rim of a patient's heartwith the suturing ring 10 unrestrained as described further below. Thesuturing ring first annulus diameter AD1 is sized with respect to theselected heart valve frame diameter to enable a valve body 50 of amechanical heart valve or a stent 40 of a tissue valve to be insertedinto the suturing ring annulus and rotated therein to a desiredorientation. Then, the suturing ring split ends 14 and 16 are secured orrestrained by an interlocking or restraining mechanism of one of thetypes described herein and equivalents thereto. The restraint ispreferably accomplished by one or more of sutures, clamps, hooks, teeth,buttons, or other ring locking mechanisms that can released even afterchronic implantation so that the heart valve mechanism can be replaced.

[0089] A preferred interlocking restraint comprises the use of one ormore suture 38 sewn through the fabric 32 overlying and through asuitable suture retainer, e.g., the illustrated suture holes 34 and 36extending through the stiffening band 12, adjacent the band split ends14 and 16, respectively. The suture 38 is pulled tight to draw the bandsplit ends 14 and 16 together to the extent permitted by the valveframe, and tied off. Thus, the stiffening band split ends 14 and 16 canbe restrained such that the second annular diameter AD2 of the suturingring 12 is defined, and the suturing ring 12 interference fits with andengages the valve frame exterior surface. In the following examples, itwill be assumed that the second annulus diameter AD2 is smaller than thefirst annulus diameter AD1.

[0090] Preferably, the interior surface 18 of the split stiffening band12 is shaped in a complimentary mating fashion to the exterior surfaceof the valve frame to entrap or lock the surfaces together when the bandsplit ends 14 and 16 are restrained. For example, it will be assumedthat the complimentary mating shapes can comprise one or more spiral orannular groove or array of groove segments or pin holes extending intothe outer surface of the valve frame or into the inner surface 18 of thesplit stiffening band 12 that receives a mating one or more spiral orannular flange or array of flange segments or pins projecting outwardfrom the other of the inner surface 18 of the split stiffening band 12or the outer surface of the valve frame.

[0091] In the depicted tissue valve embodiments, the valve stent 40comprises a wire or plastic or reinforced pyrolytic carbon stent frame42 covered with stent fabric 44 of the same materials as the suturingring fabric 32. The stent frame 42 shown in FIG. 3 can take any of theknown configurations having a cylindrical frame base 46 and a pluralityof frame posts 51, 53, and 55. An annular flange 48 is formed extendingoutward of the frame wall around the cylindrical frame base 46 that isdimensioned to be seated and retained in the annular groove 22 of thesplit stiffening band 12. The stent fabric 44 is sewn together to extendall over the interior surface of the stent frame 42, over the exteriorsurface of the posts 51, 53, and 55 and sewn together along either sideof the stent flange 48, leaving the stent flange 48 exposed.

[0092] An alternate suturing ring 10′ is depicted in FIGS. 6 and 7 thatdiffers from suturing ring 10 only in that the fabric strip ends of thesuturing ring fabric 32 are not sewn together over the band split ends14 and 16, whereby the suturing ring 10′ itself has split ends. Certainof the interlocking mechanisms contemplated by the invention may requiredirect access to the band split ends 14 and 16 in order open and closethe restraints. The suture 38 can be used to interlock and restrain theband split ends 14 and 16 when the suturing ring fabric is sewn togetheras in suturing ring 10 shown in FIG. 1 or is not sewn together as inalternate suturing ring 10′ shown in FIG. 7.

[0093]FIG. 8 is a cross-section view taken along lines 8-8 of FIG. 1illustrating the mating engagement of the fabric covered splitstiffening band 12 of the suturing ring 10 or 10′ against the outer wallof the fabric covered valve stent frame 46. In particular, the exposedannular flange 48 fits into the exposed band groove 22 in aninterference fit that holds the stent 40 firmly but enables the stent 40to be rotated when sufficient torque is applied to it during surgery.

[0094] The particular configuration of the suturing ring 10 enablessuturing ring 10 or alternate suturing ring 10′ to be used to engage andretain a conventional mechanical heart valve body 50 of the typedepicted in FIGS. 6 and 7. The simplified depiction of the valve body 50shows that the valve body outer wall 52 is cylindrical between upper andlower outwardly extending flanges 54 and 56. The annulus diameter AD2and the width of the suturing ring 10 or 10′ between axial ends 24 and26 are selected so that the interior band sidewall 18 is seated andretained within the U-shaped annular channel formed between the upperand lower flanges 54 and 56. The inwardly extending groove 22 does notplay any role in or interfere with retention of the suturing ring 10 or10′ within the U-shaped annular channel formed between the upper andlower flanges 54 and 56 as shown in FIG. 9.

[0095] The surgical steps of initially implanting a tissue valve ormechanical valve of the present invention are greatly simplified by thepresent invention. The surgical method comprises first surgicallyexposing and excising the dysfunctional native heart valve and preparingthe valvar rim 60 shown in FIG. 10 in the conventional manner. An arrayof sutures 62 is extended through the valvar rim tissue and the suturingring fabric 32 as shown in FIG. 10. The suturing thread is passedthrough the valvar rim tissue and then returned through the fabric 32.If desired, pledgets may be used to reduce the possibility of cutting ortearing the tissue when tightening the sutures 62. In this situation,double armed sutures are first passed through the valvar rim tissue andthen through the suturing ring fabric 32.

[0096] The suturing ring 10 can then be advanced over the sutures 62 andagainst the valvar rim 60 while holding the sutures 62 taut. The sutureends are then tied together against the suturing ring fabric to fix thesuturing ring 10 in place, and the suture ends are then trimmed. Thesutures 62 through the suturing ring fabric 32 are also shown in FIGS.1, 8 and 9. The connection between the suturing ring 10 and the valvarrim tissue is carefully checked in an effort to prevent development ofperivalvular leaks or dehiscence after the heart valve mechanism is inplace.

[0097] The suturing ring diameter AD1 is expanded if necessary so thatthe valve frame, e.g., the depicted valve stent 40 or the valve body 50,can then be inserted into the annulus of the suturing ring 10 and seatedas described above. The unrestrained suturing ring annulus diameter AD1is either expanded or compressed to the restrained suturing ring annulusdiameter AD2 if necessary to seat the suturing ring 10 about the valveframe. The valve frame can then be rotated to the optimal orientationwithin the suturing ring 10. The restraint, that is the suture 38 orother interlocking mechanism is then affixed to inhibit any spontaneousrotation or detachment of the valve frame from the suturing ringannulus. The valve function is checked to make certain it is orientedoptimally. If further rotation is necessary, it may be necessary torelease the restraint, rotate the valve frame, and repeat therestraining steps. The conventional surgical closures are then made.

[0098] The initial implantation procedure can be further simplified byinserting the valve frame into the stiffening ring annulus while bothare supported above and away from the valvar rim 60 by the extendedarray of sutures 62 held taut during the procedure. Thus, the valvestent 40 can be inserted into the annulus of the suturing ring 10 asshown in FIG. 10, and the assembly can be advanced over the taut arrayof sutures 62 to seat the suturing ring 10 against the valvar rim 60.The valve stent 40 can still be rotated within the suturing ring annulusto the optimal orientation before or after the suturing ring 10 issutured against the valvar rim 60 and the restraint is affixed to theband split ends 14 and 16.

[0099] In a further aspect of the invention, the sewing of the suturingring to the valvar rim in the initial implantation steps is simplifiedsuch that suture knots about the suturing ring surface can beeliminated. In this aspect, the plurality of sutures 62 that are sewnthrough the valvar rim 60 around its circumference are extended throughthe suturing ring annulus (at least in part) as shown in FIG. 11. Thesutures 62 are entrapped between the suturing ring annulus and the outerwall of the valve frame in the subsequent steps, e.g., by the valvestent 40 as shown in FIG. 12. The valve stent 40 can be inserted intothe annulus of the suturing ring 10 as shown in FIG. 12, and theassembly can be advanced over the taut array of sutures 62 to seat thesuturing ring 10 against the valvar rim 60. The valve stent 40 can stillbe rotated within the suturing ring annulus to the optimal orientationbefore or after the suturing ring 10 is sutured against the valvar rim60 and the restraint is affixed to the band split ends 14 and 16. Thefree ends of the sutures 62 are then trimmed down to the surface of thesuturing ring fabric 32 in the final implantation step prior to closure.The relatively bulky knots that can abrade tissue valve leaflets, befoci of coagulation or thrombus formation, and can interfere with bloodflow or valve operation are eliminated.

[0100] It will be understood that a mechanical valve mechanism can besubstituted for the tissue valve mechanism schematically illustrated inFIGS. 10-12.

[0101] In one simple implementation of this further aspect, the sutures62 are sewn through an axial end band or both axial end bands of thesuturing ring fabric 32 at spaced apart locations around thecircumference of the suturing ring 10 so as to support the suturing ring10 and to maintain the sutures generally evenly spaced apart. Then, theexposed ends of the sutures extending out of the suturing fabric 32 canbe tied off.

[0102] Alternatively, each of the sutures 62 can be extended through thesuturing fabric 32 and through an array of suture guides formed in orsupported by the split stiffening band 12. For example, the sutures 62can be sewn through the preformed holes or slots 28 through the splitstiffening band 12 that are also used in stitching the suturing ringfabric 32 to the split stiffening band 12. The sutures 62 are brought upfrom the valvar rim 60 through the suturing ring annulus and thenextended outward via an attached suture needle (not shown) through theoverlying suturing ring fabric 32 and preformed holes or slots 28, backinward around the suturing ring fabric 32 overlying the band axial end24, and then back outward through the overlying suturing ring fabric 32and preformed holes or slots 28. Conversely, the sutures 62 are broughtup from the valvar rim 60 through the suturing ring annulus, broughtoutward around the suturing ring fabric 32 overlying the band axial end24, then extended via the attached suture needle back inward through theoverlying suturing ring fabric 32 and preformed holes or slots 28, andthen back outward around the suturing ring fabric 32 overlying the bandaxial end 24.

[0103]FIG. 13 illustrates the entrapment of a suture 62 extending fromthe valvar rim 60 between the inner wall of the suturing ring 10, 10′and the outer wall of the stent 40, particularly illustrating the seatedstent flange 48 within the suturing ring groove 22. Advantageously, thefree ends of the sutures 62 can routed through the suturing ring fabric32 and upper suture grooves or holes 28, around the upper band axial end24 and suturing ring fabric 32, pulled tight to affix the suturing ring10, 10′ snugly against the valvar rim 60, and tied off using a singlehitch 64 as shown in FIG. 13. FIG. 14 illustrates the entrapment of asuture 62 extending from the valvar rim 60 between the inner wall of thesuturing ring 10, 10′ and the outer wall of the mechanical valve body50, particularly illustrating the suturing ring 10, 10′ seated in theU-shaped channel of the valve body 50 as described above. The free endsof the sutures 62 can routed through the suturing ring fabric 32 andupper suture grooves or holes 28, around the upper band axial end 24 andsuturing ring fabric 32, pulled tight to affix the suturing ring 10, 10′snugly against the valvar rim 60, and tied off using a double hitch 66as shown in FIG. 14. The single hitch 64 or double hitch 66 can beefficiently made by the surgeon manipulating the suturing needle to makethe hitch loop(s), pulling the sutures 62 tight, and then snipping thesuture off close to the single hitch 64 or double hitch 66. The singlehitch 64 or double hitch 66 can be used to attach the suturing ring 10,10′ to the valvar rim 60 to receive any type of mechanical or tissueheart valve mechanism. The single hitch 64 or double hitch 66 isrelatively easier to accomplish and smaller in comparison to thetraditionally used single or double square knots.

[0104] Further implementations of the suture guides of this secondaspect of the invention are illustrated in FIGS. 15 and 16, wherein thesuturing ring fabric 32 and stent fabric 44 are not shown forconvenience of illustration. In these embodiments, the routing of eachsuture 62 is accomplished using suture guides supported by or formed inthe interior band sidewall 18. For example, a modified split stiffeningband 12′ is employed having a pair of flanges 70 and 72 extending inwardabove and below the groove 22 that fit on either side of the stentflange 48. A plurality of axially aligned pairs of suture guides orholes 74 and 76 are formed through the band flanges 70 and 72,respectively arrayed about the circumference of the split stiffeningband 12′. One or more suture 62 can be extended through each axiallyaligned pair of suture holes 74, 76 and across the intervening groove22. The sutures 62 can be employed to suture the suturing ring to thevalvar rim 60 as shown in FIGS. 11 and 12 and are then entrapped withinthe groove 22 by the stent flange 48 when the band split ends 14 and 16are restrained.

[0105] Furthermore, the band flanges 70 and 72 are preferably notched orslotted from the suture holes 74, 76 to the flange edges to enable theone or more suture 62 to be laterally, rather than axially, insertedinto the axially aligned suture holes 74, 76. The split stiffening band12 is flexible enough that the band split ends 14 and 16 can beseparated apart to widen the slots or notches enough to pass the suturelaterally into the axially aligned suture holes 74, 76 whereupon theslots or notches would then narrow upon release of the separation force.

[0106] The axially aligned suture holes are not employed in the furtheralternative split stiffening band 12″ depicted in FIG. 16. Instead, theillustrated convoluted or circuitous path of each suture 62 around thestent flange 48 and the band flanges 70 and 72 and optionally through anupper suture slot 28 increases the resistance to release of each suture62.

[0107] In these ways, the suturing of the suturing ring to the valvarrim is greatly simplified, resulting in fewer and smaller sized knotsbeing required. Tissue ingrowth into the interstices of the suturingring fabric occurs in time, and the sutures may become unnecessary toretain the suturing ring 10 in place. The single hitch 64 or doublehitch 66 is expected to be sufficient to hold the suturing ring 10, 10′in place during the removal of a dysfunctional heart valve mechanism andreplacement with a new heart valve mechanism.

[0108] FIGS. 17-19 illustrate alternative or additional restraintmechanisms incorporated into the split stiffening band 12 for closingand opening the split stiffening band 12. At least the restraintmechanisms depicted in FIGS. 17 and 18 can be enclosed within thesuturing ring fabric sewn together as illustrated by suturing ring 10 ofFIG. 1 or exposed at the ends of the suturing ring fabric as illustratedby the suturing ring 10′ of FIGS. 6 and 7.

[0109] In FIG. 17, a spring 82 is integrally formed to extend betweenthe band split ends 14 and 16 maintaining the first annulus diameterAD1. The split band ends 14 and 16 can be separated apart to theincreased second annulus diameter AD2 through application of forceovercoming the spring tension to receive or remove a valve frame. Thespring force then brings the split band ends 14 and 16 together when theforce is removed. The spring force retains the valve frame seated withinthe suturing ring annulus and any of the sutures 62 inserted between thevalve frame and the suturing ring as described above.

[0110] In FIG. 18, the band split ends 14 and 16 are modified to havelongitudinally extending mating teeth or hooks 84 and 86 that arenormally interlocked to prevent spreading apart of the band split ends14 and 16 and provide the first annulus diameter AD1. Opposed axialforces can be applied to release and then set the mating teeth or hooks84 and 86 together to expand the annulus diameter to the second annulusdiameter AD2 to receive or remove a valve frame. Force can then beapplied longitudinally to reset the mating teeth or hooks 84 and 86 andbrings the split band ends 14 and 16 back closer together. The matingteeth or hooks 84 and 86 retain the valve frame seated within thesuturing ring annulus and any of the sutures 62 inserted between thevalve frame and the suturing ring as described above.

[0111] In FIG. 19, the band split ends 14 and 16 are modified to have alongitudinally extending restraint band 88 having snaps or buttons thatare received in the suture holes 34 and 36 to prevent spreading apart ofthe band split ends 14 and 16 and provide the first annulus diameterAD1. One of the snaps or buttons can be released from one of the sutureholes 34 and 36 by use of a forceps or the like to expand the annulusdiameter to the second annulus diameter AD2 to receive or remove a valveframe. The snaps or buttons can then be reapplied to retrain the splitband ends 14 and 16 back closer together. The restraint band retains thevalve frame seated within the suturing ring annulus and any of thesutures 62 inserted between the valve frame and the suturing ring asdescribed above.

[0112] A preferred method incorporating both aspects of the invention ofsurgical implantation of the suturing rings 10, 10′ of the presentinvention and fixation of a tissue valve stent 40 or a mechanical valvebody 50 into the suturing ring annulus is depicted in FIG. 20. In thismethod, the suturing ring 10, 10′ is first surgically implanted in stepsS100-S104 to the prepared valvar rim. The surgeon can either use aplurality of sutures 62 fitted through each one or adjacent pairs of theabove-described suture guides or a single running suture fitted throughall of the suture guides. The danger that the single running suture maybreak during chronic implantation and cause the suturing ring 10, 10′ toloosen from the valvar rim 60 is overcome because multiple parallelsegments of the single running suture are entrapped between thestiffening ring 12 and the valve frame 40 or 50 that would remain firmlyattached to the valvar rim 60.

[0113] Preferably, in either case, the suture(s) 62 are sewn through asuture guide, then inferiorly through a site of the valvar rim that thesuture guide will be aligned with, then back superiorly through a siteof the valvar rim that the adjacent suture guide is aligned with, andthen through the adjacent suture guide in step S100. The suturing isfacilitated because the surgeon's view of the sites of the valvar rim isnot obstructed by any valve structure. In addition, the surgeon canextend instruments or a finger through the empty suturing ring annulusto effect sewing the suture(s) through the sites of the valvar rim 60 tospeed the process and avoid damage to the valvar rim that could otherwise occur.

[0114] The suturing ring 10, 10′ can be suspended on taut suture(s) 62in alignment with valvar rim 60 as shown in FIG. 11 and advanced againstthe valvar rim 60 over the taut suture(s) in step S102. One way ofholding the suturing ring 10, 10′ using a tool 90 is depicted in FIG.22. Tool 90 is formed of an elongated handle 92 attached to a spanner 94having a plurality of arms, e.g., arms 96, 98, 100, 102, that extend tothe suturing ring annulus and are sutured to the stiffening ring 10, 10′by tool sutures 97, 99, 101 and 103. The stiffening band and the arms96, 98, 100, 102 are formed with special suture holes that tool sutures97, 99, 101 and 103 extend through and tied. The tool sutures 97, 99,101 and 103 are adapted to be cut when the suturing ring 10, 10′ issnugged up against the valvar rim 60.

[0115] The suturing ring 10, 10′ is snugged up against and locked to thevalvar rim 60 by tying a knot in the single running suture or knottingthe ends of the individual sutures 62 in step 104. Preferably, thesuture(s) 62 are inserted through the upper suture slots 28 as shown inthe examples of FIGS. 13 and 14, and the single or double slip hitch 64or 66 is formed in the turns of the suture extending over the suturingring fabric 34. Slip hitches are easier to form by the surgeon usinginstruments than a square knot.

[0116] The suturing ring annulus is adjusted as necessary in step S106so that the valve frame 40 or 50 is then inserted into it. For example,the gap G can be widened as necessary to receive the flange 48 withinthe slot 22 or to fit the suturing ring 10, 10′ into the U-shapedchannel of the mechanical valve body 50 as described above. The valveframe 40 or 50 is inserted into, rotated and seated in steps S108, S110,and S112 in the ways described above.

[0117] The valve mechanism is preferably mounted to a valve holder toolas it is inserted into and seated in the suturing ring annulus. Forexample, a stent holder 110 is illustrated in FIG. 23 comprising a stentholder handle 112 attached to a stent holder spanner 120 having threefingers 114, 116 and 118 that extend over and against the stent strutsand thereby frictionally engage the stent 40. A suture may also beplaced around or through holes in the three fingers 114, 116 and 118 andthe corresponding stent struts to hold the stent 40. The stent holder110 is manipulated to insert the stent 40 into the sewing ring annulusin step S108. The lengths of the three fingers 114, 116, 118 areselected so that the outwardly ending free ends of the three fingers114, 116, 118 bear against the suturing ring 10, 10′ when the stentflange is positioned to be seated in the groove of the stiffening ringas described above. The outwardly ending free ends of the three fingers114, 116, 118 bearing against the suturing ring 10, 10′ when the stentflange is properly seated in the groove of the stiffening ring 10, 10′prevent the surgeon from extending the stent 40 all the way through thesuturing ring annulus.

[0118] The interlocking restraint of one of the above-described types isoperated in step S114. Preferably, the interlocking restraint is theabove-described suture 38, and that is sewn through the suture holes 34and 36, drawn tight, and either tied or thermally welded against thesuturing ring fabric in step S114.

[0119] The excess suture length of the running suture or lengths of theseparate sutures 62 are then trimmed in step S116. Advantageously,tightened slip hitches 64 or 66 are small in size and will remain inplace when a replacement surgical procedure of the types described aboveare undertaken.

[0120] The various aspects of the suturing ring 10, 10′ of the presentinvention employing any of the interlocking restraints presents thesurgeon with a wide range of possible ways of surgically implanting itupon or against the valvar rim 60. The suturing ring 10, 10′ of thepresent invention can be supplied with the outwardly extending collar toenable traditional suturing through it as depicted in FIGS. 1, 8 and 9.However, the surgeon can ignore the suturing ring fabric collar andfollow any of the above-described techniques, e.g., steps S100-S104 toentrap segments of the suture(s) 62 between the valve frame and thesuturing ring annulus.

[0121] It is desirable in many instances to implant a heart valveprosthesis in or to a valvar rim 60 having as large a valve annulus aspossible to enable maximal unobstructed blood flow through it when theoccluder is not seated. Advantageously, a larger diameter suturing ring10, 10′ (accommodating a larger diameter valve mechanism and valveannulus) can be selected to fit the valvar rim if the surgeon followsany of the above-described techniques, e.g., steps S100-S104 to entrapsegments of the suture(s) 62 between the valve frame and the suturingring annulus rather than suturing through the fabric collar. Models ofsuturing ring 10, 10′ can be provided with a minimal sized outwardlyextending collar of the suturing ring fabric 32 and a relatively largersuturing ring annulus for selection by a surgeon intending to follow anyof the above-described techniques, e.g., steps S100-S104 to entrapsegments of the suture(s) 62 between the valve frame and the suturingring annulus.

[0122] All of the above described methods of initially implanting thesuturing ring 10, 10′ are facilitated by having the ability to seethrough, extend the surgeon's finger or instruments through and extendsutures through the open suturing ring annulus. A further simplified wayof suturing the suturing ring 10, 10′ to a valvar rim 60 (which inpractice may simply be the tubular valvar annulus remaining aftersurgical excision of the native heart valve) employing a single suture62 is depicted in FIG. 21. This method, the suturing ring 10, 10′ isheld within or against the valvar annulus constituting the valvar rim 60by a suitable instrument. A number of loops of the suture 62 are made bythe surgeon extending entirely around the suturing ring 10, 10′ via theopen suturing ring annulus and through adjoining valvar tissue under orwithin valvar rim 60. The suture ends can be drawn through any selectedadjacent pair of any of the suture holes 28, 30, 34, 36 depicted in FIG.5 and/or just through the suturing ring fabric 32. The suture 62 ispulled taut, the suture ends are tied together in a suture knot 68, andthe excess suture is trimmed away. In this way, the surgeon can implantthe maximum diameter suturing ring 10, 10′ in a tubular valvar annulusthat is otherwise difficult sized only a single knot 68 is necessary. Ofcourse, it would also be possible to form separate hitches in the sutureends as described above with respect to FIGS. 13 and 14.

[0123] Then, steps S106-S116 of FIG. 20 are followed to affix the valvemechanism in place. The suture segments are entrapped between thesuturing ring annulus and the valve frame as described above. Theseentrapped segments of the suture 62 still hold the suturing ring 10, 10′in place even if the suture 62 happens to break at any point along itslength.

[0124] The surgical steps of replacing a tissue valve or mechanicalvalve at a later time are greatly simplified by the present invention.All that is necessary to do is to: 1) Surgically expose the chronicallyimplanted valve mechanism and suturing ring assembly and clean thetissue overgrowth away; 2) Locate the suturing ring restraint; 3)Release the restraint; 4) Insert a scalpel or a blunt probe into theinterface between the split ring and the valve frame starting from thesplit end, 5) Gently peel the split ring from the valve frame along thecircumferential direction using the same instrument, 6) Remove the valvemechanism from the annulus of the suturing ring; 7) Insert and seat thenew replacement valve mechanism into the annulus; 8) Attach thereplacement valve mechanism therein following any of the above-describedtechniques depending upon the particular design of the suturing ring andthe replacement valve mechanism; and 9) Complete the surgical closure.

[0125] As noted above, the restraint can be a suture sewed through thesuturing ring fabric and suture holes adjacent the split ends of thestiffening ring. The suture can be identified at the bunched fabric thatthe suture is sewn through. The fabric can be marked or colored toindicate where the suture is located to be cut in step 3), and a newsuture is to be sewn in the attachment in step 8). If the alternativerestraints illustrated in FIGS. 17-19 are employed, then they are openedin step 3) and closed in step 8).

[0126] Advantageously, this process allows the dysfunctional valvemechanism to be replaced by the same or a different type of valvemechanism that can be seated into the annulus of the suturing ring instep 7). However, the chronically sewn-in suturing ring can also be usedas a docking station for an incompatibly dimensioned heart valveprosthesis comprising a tissue or mechanical heart mechanism that issupplied with an integral suturing ring. In this case, step 8) can bereplaced by placing the integral valve suturing ring within or onto theannulus of the chronically sewn-in suturing ring and suturing themtogether.

[0127] Referring now to FIGS. 24a-b, in yet another embodiment of theinvention, a band 120 is applied to a valve having a suturing ring inorder to secure sutures in place. The band 120 has substantially thesame properties as the band 12 discussed previously. Band 120 has a topportion 122, an outside portion 124, and a bottom portion 126. The topportion 122 and bottom portion 126 include inwardly extendingcircumferential flanges 128, 130 respectively. Centrally located on theband 120 is a third inwardly extending circumferential flange 132 thatis longer than the other flanges 128, 130. The band includes split ends134, 136, which are secured together by a restraint mechanism such as asuture 140 that is capable of locking the position of the split ends134, 136. The suture 140 or other restraint mechanism is preferable madefrom a resilient material such as nitinol, which can bepseudoelastically deformed to open the band 120 and then released toreturn it to an undeformed condition, thereby closing the band 120 bypulling the split ends 134, 136 together. Alternatively, a nitinolrestraint mechanism can be used as a shape memory device in which therestraint mechanism responds to warming to body temperature bytransforming the restraint from its martensitic state to its austeniticstate. Such a phase transformation can pull the split ends 134, 136together as the device is warmed. Other restraint mechanisms can be usedas well, but most preferably the selected restraint mechanism permitsthe surgeon implanting the device to remove or loosen the restraintmechanism if the band 120 must be removed, released or repositioned.

[0128] Valve 150 can be a mechanical or tissue valve having a frame orstent. Valve 150 is shown to be a tissue valve having a frame portion152 that includes a first, outwardly-extending circumferential flange154 at the top of the frame portion 152 and a second,outwardly-extending circumferential flange 156 at the bottom of theframe portion 152. As shown in FIG. 24b, the flanges 154, 156 are sizedto fit within recesses in the band 120 between inwardly extendingflanges 128, 130, 132 and are spaced apart to permit the centrallylocated flange 132 to reside between the flanges 154, 156. The band 120and frame portion 152 thereby cooperate to form an interlockingengagement that can engage and restrain the movement of a suture 160that may be introduced and secured between them. It will be appreciatedthat many other configurations of interlocking elements can be used toengage and restrain the movement of a suture. Preferably, suchinterlocking elements are characterized by a tortuous path for thesuture and closely mating surfaces between the band 120 and the frameportion 152.

[0129] In operation, the valve 150 is secured by a plurality of sutures160 to a prepared valvar rim 162 by bringing the sutures through asuture ring 164, through a portion of the valvar rim 162 and returningthe suture through the suture ring 164. The ends of the sutures 160extending away from the valvar rim 162 preferably run through the suturering 164 at points near the outer portion of the frame portion 152. Whenall of the sutures 160 have been positioned, the suture ring 164 ispressed against the valvar rim 162 and the sutures 160 are drawn awayfrom the suturing ring 164 to take up any slack. The band 120 is thenplaced over the valve 150 and advanced into position over the frameportion 152. In order to permit the band 120 to achieve a matingengagement with the frame portion 152, the split ends 134, 136 arespaced apart sufficiently to permit the inwardly extending flanges 130,132 to clear outwardly extending flanges 154, 156. The split ends 134,136 may be brought to the spaced apart position by prying them apartslightly, if that is necessary. The restraint mechanism such as thesuture 140 is preferably affixed to the split ends 134, 136 prior to thetime the band 120 is placed over the frame portion 152. If the restraintmechanism is a resilient restraint, such as a spring, the restraint canbe in place as the split ends 134, 136 are brought to a spaced apartposition and then simply released. Alternatively, a nitinol restraintcan be allowed to warm to body temperature to pull the split ends 134,136 together. In yet another way, a restraint mechanism such as a suture140 can be loosely positioned in apertures on the spilt ends 134, 136and can be brought from an unsecured state to a taut, secured state bythe surgeon after the band 120 is placed over the frame portion 152. Ifdesired, a suitable ring-spreading tool such as those known in the artcan be used to facilitate the correct positioning of the split ends 134,136. Once the band is in a mating position with the frame portion 152,the split ends 134, 136 can be drawn together in order to urge theflanges 128, 130, 132 of the band 120 into contact with the sutures 160and to drive the sutures 160 into the recesses in the frame portion 152defined by the flanges 154, 156 and into recesses defined in the band120 by the flanges 128, 130, 132. The band 120 then secures the sutures160 from movement and excess suture material extending above the topportion 122 of the band may be removed. In order to facilitate a rapidsurgical procedure, the sutures so secured between the band 120 and theframe portion 152 are secured entirely by the band 120 and frame portion152 without the need to tie any knots in the sutures 160. If the surgeonfinds it necessary to tighten any of the sutures 160 after the band 120is secured over the frame portion 152, the split ends 134, 136 can bedrawn apart until the sutures to be tightened are moveable. The sutures160 can then be pulled tight and the band 120 drawn against the frameportion 152 to resecure the sutures 160.

[0130] Referring now to FIGS. 25a-b and FIGS. 26a-e, in yet anotherembodiment of the invention, a band 220 is also applied to a valvehaving a suturing ring in order to secure sutures in place. Band 220 ismade in a closed ring configuration with a top portion 222 joined at anoutside edge to an outside portion 224. The top portion 222 comprises aninwardly extending flange that also joins at an inner edge with adownwardly extending circumferential flange 228. The band 220 includes aplurality of splits 234 that extend through the outside portion 224 froma bottom edge 226 upward to a central portion of the outside portion224. The splits 234 do not extend completely through the band 220. Thesplits 234 are preferably spaced around the circumference of the band220 such that pairs of adjoining splits create tab portions 236 aroundthe circumference of the band 220. The tab portions 236 can also extendpartially below the bottom edge 226 of the ring as in FIG. 26e. Also,the tab portions 236 may be made independent of any splits as shown inFIG. 26d where the tab portions 236 are shown protruding below thebottom edge 226. A barbed portion 240 is on the lower edge of each ofthe tab portions 236, as best appreciated in cross-section in FIG. 26c.The barbed portions 240 include a substantially flat upper portion 242and an angled lower portion 244. Portions of the band 220 between thetab portions 236 can be formed without a barbed portion as shown in FIG.26b. The tab portions are designed so that they may be resilientlyspread radially outwardly at the lower, barbed portion 240 and thenreleased to return them to an unspread position. The tab portions 236can, by their resilient deformation, form a locking mechanism with acomplimentary structure on a frame portion 252 of a valve 250 in alocking fit. Locking mechanisms employing structures other than a barbshape can also be used so long as they provide a positive, lockingattachment between the band 220 and the frame portion 252. Preferably,multiple tabs are used on the band 220 and are spaced around thecircumference of the band 220 in order to provide an even lockingattachment between the band 220 and frame portion. Two or more such tabsare preferred.

[0131] Referring now to FIGS. 25a-b and FIGS. 27a-b, valve 250 can be amechanical or tissue valve having a frame or stent. Valve 250 is shownto be a tissue valve having the frame portion 252 that includes a first,outwardly-extending circumferential flange 254 with an upwardlyextending portion 256 that forms a circumferential recess in the flange.The recess is therefore open in the outflow side of the valve. As shownin FIG. 25b and FIGS. 27a-b, the flange 254 and upwardly extendingportion 256 are sized to fit within the recess in the band 220 while thedownwardly extending flange 228 of the band is sized to fit within therecess in the flange 254. Preferably, the upwardly extending portion 256is tapered slightly on its outer edge such that the tab portion 236 willbe deflected outwardly by contact with the taper. The band 220 and frameportion 252 thereby cooperate to form an interlocking engagement inwhich the barb portion 240 catches on a portion of the frame portion 252and holds the band 220 and frame portion together. As shown in FIG. 25band FIG. 28a, the mating of the frame portion 252 and band 220 in thismanner can prevent movement of a suture 260 that may be introduced andsecured between them. Because the barb portion 240 has an angled lowerportion 244, and because of the taper on the upward extending portion256 the placement of the band on the flange is a simple press fit. Thatis, the band 220 can be readily pressed onto the flange 254 by astraight downward motion that deflects the tab portions 240simultaneously and causes them to lock simultaneously in a locking fitonto a complementary structure on the flange 254. In the embodimentshown, the barb portion engages the inflow side of the flange 254. Itwill be appreciated that many other configurations of the lockingmechanism can be used, including placing the locking barbs or elementson the flange rather than on the band and applying a band that has acomplementary structure for locking the barbs to the band. Thus, a bandwithout splits or tabs could be used according to the invention toengage and restrain the movement of a suture.

[0132] In operation, the valve 250 is secured by a plurality of sutures260 to a prepared valvar rim 262 by bringing the sutures through asuture ring 264, through a portion of the valvar rim 262 and returningthe suture through the suture ring 264. The ends of the sutures 260extending away from the valvar rim 262 preferably run through the suturering 264 at points near the outer portion of the frame portion 252. Whenall of the sutures 260 have been positioned, the suture ring 264 ispressed against the valvar rim 262 and the sutures 260 are drawn awayfrom the suturing ring 264 to take up any slack. The band 220 is thenplaced over the valve 250 and advanced into position over the frameportion 252 and pressed onto the frame portion 252 until a locking fitis achieved between the barbs 240 and the frame portion 252. Preferably,the frame portion 252 is designed to provide a circumferentiallycooperating portion that will receive the barbs 240 in any relativerotational orientation of the band 220. Alternatively, the frame portioncould be provided with a mark or indicator that could be aligned with asimilar mark or indicator on the band in order to align the components.If the surgeon finds it necessary to tighten any of the sutures 260after the band 220 is secured over the frame portion 252, the tabportions 236 can be resiliently drawn away from the frame portion 252 sothat the barbs 240 are released from engagement with the frame portion.The band 220 is then drawn upward until the sutures to be tightened aremoveable. The sutures 260 can then be pulled tight and the band 220 canagain be pressed against the frame portion 252 to resecure the sutures260.

[0133] The process for pressing the band 220 onto the frame portion 252can be facilitated by using a pressing tool 270 as set forth in FIGS.29a-b. The pressing tool 270 includes a cylindrical body 272 and ahandle portion 280. The cylindrical body 272 includes a shoulder portion274 that is configured to engage the band 220. The handle portion 280includes a portion that is interior to the body 272 and a portion thatis exterior to the body and is free to rotate with respect to the body272 on threads 282 engaging complimentary threads on the body 272. Theinterior of the body 272 is sized to receive the valve and any valveholder and handle that may be attached to the valve during the surgicalprocedure. The interior portion of the handle portion is sized to engagewith the valve and valve holder. In operation, the pressing tool 270 isplaced over the valve and with the band engaged with the body 272 and inplace against the frame portion 252, the body is manually rotated toadvance the body 272 over the threads 282 relative to the handle 280.This advances the band 220 onto the frame portion 252 until the closureis achieved between the band 220 and frame portion 252. Alternatively,another pressing tool 271 can be used to facilitate positioning of theband 220 as shown in FIGS. 29c-d. A cylindrical body portion 273includes retention tabs 277 that are configured to grip the band 220.Preferably three or more such tabs 277 are evenly spaced around the body273 to grip the band 220 evenly at several places. Threaded apertures275 are on an upper portion of the body 273 in order to permit the bodyto be secured to the handle of a valve holder by locking elements 289. Asleeve 281 has screw threads 285 on an outer portion thereof and a notch287 configured to provide an opening for tab 277. The sleeve 281 fitsover the body 273. A cap 283 configured to fit over an upper portion ofbody 273 includes internal screw threads (not shown) which are intendedto mate with screw threads 285 on the sleeve 281. In operation, the tool271 slides over the handle 296 of the valve holder and the lockingelements 289 are screwed into locking engagement with the handle 296.The cap 283 is then manually rotated which causes the sleeve 281 to beadvanced over the body 273. As the sleeve 281 is advanced, it contactsthe band 220 and pushes the band 220 off of the retention tabs 277 andinto engagement with the flange of the frame portion.

[0134] The process for pressing the band 220 onto the frame portion 252can be facilitated by using a suture tensioning tool 290 as set forth inFIGS. 30a-b and 31. The suture tensioning tool 290 is mounted to thehandle 296 for the valve holder 298. The suture tensioning tool 290includes notches 292 or other suture tensioning devices around itscircumference. In operation, the valve 250 is secured by a plurality ofsutures 260 to a prepared valvar rim 262 by bringing the sutures througha suture ring 264, through a portion of the valvar rim 262 and returningthe suture through the suture ring 264. The ends of the sutures 260extending away from the valvar rim 262 are drawn up to the suturetensioning tool 290 and are retained thereto in the notches 292. Aftereach of the sutures 260 is secured in position on the suture retainingtool, with any slack in the sutures 260 removed, the band 220 andpressing tool 270 are advanced over the handle 296, suture tensioningtool 290 and valve 250. With the handle 296 of the valve holder 298 andthe handle of the pressing tool held stationary in one hand of thesurgeon, the surgeon turns the body 272 until the band 220 locks ontothe frame portion 252. The tools 270, 290 can then be removed and anyexcess material can then be removed from the ends of the sutures 260.

[0135] All patents and publications referenced herein are herebyincorporated by reference in their entireties.

[0136] Although particular embodiments of the invention have beendescribed herein in some detail, this has been done for the purpose ofproviding a written description of the invention in an enabling mannerand to form a basis for establishing equivalents to structure and methodsteps not specifically described or listed. It is contemplated by theinventors that the scope of the limitations of the following claimsencompasses the described embodiments and equivalents thereto, includingmonitors, now known and coming into existence during the term of thepatent. Thus, it is expected that various changes, alterations, ormodifications may be made to the invention as described herein withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

1. A heart valve prosthesis comprising an annular valve body comprisinga frame and a suturing ring, the frame including at least one outwardlyextending annular flange adjacent to the suturing ring; a bandcomprising at least one inwardly extending annular flange that iscapable of engagement with the annular flange of the frame such that atortuous path is formed between the annular flange of the frame and theannular flange of the band that can engage and restrain a suture placedtherein; and at least one split portion on the band adapted to lock theband in engagement with the flange of the frame.
 2. The heart valveprosthesis of claim 1 wherein the prosthesis is a tissue valve.
 3. Theheart valve prosthesis of claim 1 wherein the frame is a stent.
 4. Theheart valve prosthesis of claim 1 wherein the frame has at least twoannular flanges.
 5. The heart valve prosthesis of claim 4 wherein theband has at least three annular flanges.
 6. The heart valve prosthesisof claim 1 wherein the split portion includes two split ends.
 7. Theheart valve prosthesis of claim 6 wherein the split ends are secured bya restraint mechanism.
 8. The heart valve prosthesis of claim 7 whereinthe restraint mechanism includes a resilient material.
 9. The heartvalve prosthesis of claim 8 wherein the resilient material is nitinol.10. The heart valve prosthesis of claim 7 wherein the restraintmechanism includes a suture.
 11. The heart valve prosthesis of claim 1wherein the band includes a plurality of splits that extend partiallythrough the band.
 12. The heart valve prosthesis of claim 11 wherein theplurality of splits define at least one locking tab on the band.
 13. Theheart valve prosthesis of claim 12 wherein the band includes at leasttwo locking tabs.
 14. The heart valve prosthesis of claim 12 wherein thelocking tab includes at least one barbed portion.
 15. The heart valveprosthesis of claim 14 wherein the barbed portion is capable of engaginga portion of the flange of the frame on an inflow portion of the flange.16. The heart valve prosthesis of claim 1 wherein the prosthesis is amechanical valve.
 17. A heart valve prosthesis comprising an annularvalve body comprising a frame and a suturing ring, the frame includingat least one outwardly extending annular flange adjacent to the suturingring, the annular flange having at least one recess formed on an upper,outflow side of the flange; a band comprising at least one inwardlyextending annular flange that is capable of engagement with the annularflange of the frame, including a portion of the flange capable ofengagement with the at least one recess formed on the annular flange ofthe frame, such that a tortuous path is formed between the annularflange of the frame and the annular flange of the band that can engageand restrain a suture placed therein; and at least one locking elementon one of the band or the flange of the frame adapted to lock the bandin engagement with the flange of the frame.
 18. The heart valveprosthesis of claim 17 wherein the prosthesis is a tissue valve.
 19. Theheart valve prosthesis of claim 17 wherein the frame is a stent.
 20. Theheart valve prosthesis of claim 17 wherein the locking element includesat least one locking tab.
 21. The heart valve prosthesis of claim 20wherein the locking tab is on the band.
 22. The heart valve prosthesisof claim 20 wherein the locking tab is on a flange of the frame.
 23. Theheart valve prosthesis of claim 20 wherein the locking element includesat least two locking tabs.
 24. The heart valve prosthesis of claim 20wherein the locking tab includes at least one barbed portion.
 25. Theheart valve prosthesis of claim 24 wherein the barbed portion is capableof engaging a portion of the flange of the frame on an inflow portion ofthe flange.
 26. The heart valve prosthesis of claim 17 wherein theprosthesis is a mechanical valve.
 27. A heart valve prosthesiscomprising an annular valve body comprising a frame and a suturing ring,the frame including at least one outwardly extending annular flangeadjacent to the suturing ring; a band comprising at least one inwardlyextending annular flange that is capable of engagement with the annularflange of the frame, including a portion of the flange capable ofengagement with a portion of the annular flange of the frame, such thata tortuous path is formed between the annular flange of the frame andthe annular flange of the band that can engage and restrain a sutureplaced therein; and at least one locking tab on one of the band or theflange of the frame adapted to lock the band in engagement with theflange of the frame.
 28. The heart valve prosthesis of claim 27 whereinthe prosthesis is a tissue valve.
 29. The heart valve prosthesis ofclaim 27 wherein the frame is a stent.
 30. The heart valve prosthesis ofclaim 27 wherein the locking tab is on the band.
 31. The heart valveprosthesis of claim 27 wherein the locking tab is on a flange of theframe.
 32. The heart valve prosthesis of claim 27 wherein the prosthesisincludes at least two locking tabs.
 33. The heart valve prosthesis ofclaim 27 wherein the locking tab includes at least one barbed portion.34. The heart valve prosthesis of claim 33 wherein the barbed portion iscapable of engaging a portion of the flange of the frame on an inflowportion of the flange.
 35. The heart valve prosthesis of claim 27wherein the prosthesis is a mechanical valve.
 36. A heart valveprosthesis comprising an annular valve body comprising a frame and asuturing ring, the frame including at least one outwardly extendingannular flange adjacent to the suturing ring; a band comprising at leastone inwardly extending annular flange that is capable of engagement withthe annular flange of the frame, such that a tortuous path is formedbetween the annular flange of the frame and the annular flange of theband that can engage and restrain a suture placed therein; and at leastone locking element on the band adapted to lock the band in engagementwith an inflow side of the flange of the frame.
 37. The heart valveprosthesis of claim 36 wherein the prosthesis is a tissue valve.
 38. Theheart valve prosthesis of claim 37 wherein the frame is a stent.
 39. Theheart valve prosthesis of claim 36 wherein the locking element includesat least one locking tab.
 40. The heart valve prosthesis of claim 39wherein the locking element includes at least two locking tabs.
 41. Theheart valve prosthesis of claim 39 wherein the locking tab includes atleast one barbed portion.
 42. The heart valve prosthesis of claim 36wherein the prosthesis is a mechanical valve.
 43. A system forreplacement of a heart valve comprising: A heart valve prosthesiscomprising an annular valve body having a frame and a suturing ring, theframe including at least one outwardly extending annular flange adjacentto the suturing ring; a band comprising at least one inwardly extendingannular flange that is capable of engagement with the annular flange ofthe frame, such that a tortuous path is formed between the annularflange of the frame and the annular flange of the band that can engageand restrain a suture placed therein; at least one locking elementadapted to lock the band in engagement with the flange of the frame; avalve holder affixed to the heart valve prosthesis; a handle extendingfrom the valve holder; and a tool having a portion adapted for matingwith a portion of the band and adapted to be advanced over the handleand over the valve holder to apply the band in mating engagement withthe flange of the frame.
 44. The system of claim 43 further comprising asuture tensioning tool mounted on the handle.
 45. A method for replacinga heart valve comprising: advancing a heart valve prosthesis having anannular valve body having a frame and a suturing ring into position on aprepared valvular rim, advancing a plurality of sutures through thesuturing ring and the valvular rim and outward of a flange extendingfrom the frame; advancing a band over the valve and over the sutures ata proximal, outflow end of the valve until the band engages the flange,thereby capturing the sutures between the band and the flange.
 37. Themethod of claim 36 further comprising locking the band to the flange.46. The method of claim 36 further comprising applying a tool having aportion adapted to mate with a portion of the band to the band as it theband is advanced into engagement with the flange.